Development of Gas-blow Hot Stamping Method for Achieving Integrated Components.

Masahiro Kubo･Satoshi Shirakami (Nippon Steel Corporation)･Noboru Itagaki (Sumitomo Heavy Industries, Ltd.)･Manabu Nishijima (Imanishi Manufacturing Co.,Ltd.)･Hiroshi Yoshida (Nippon Steel Corporation)

The author's group has been developed element technologies for parts integration by hot stamping. In this study, we developed a gas-blow hot stamping method that produces closed sections in a single step from sheet steel materials, and also conducted prototype tests to verify the formability and the compont properties.

Development of Large-scale Integral Forming Technology by Hot Stamping

Kenta Ikegami･Masahiro Kubo･Satoshi Shirakami･Hiroshi Yoshida (Nippon Steel)

We developed new large-scale integral forming technology by hot stamping. The new forming method enables both bend forming from vertical direction and draw forming from lateral direction in one stroke hot stamping. We integrally formed prototype surrounding rear floor panel including wheel-house-inner by using new forming method actually. Further, we demonstrate that the integrally formed structure with hot stamping materials contribute to the improvement of collision performance.

Development of Resistance Spot Welding Technology Using Pulsed Current Waveform Control and Automatic Off-Time Control for Three Sheets Stacks with High Sheet Thickness Ratio (Part 1)
-CDC New Spot Welding Technology-

Shinya Watanabe･Hitoshi Saito･Xihao Tan (Honda motor)･Hiroki Toyoda･Rinsei Ikeda (Osaka Univ.)

As more and more cars are being converted to BEVs, vehicle body requirements for protecting passengers and batteries are becoming stricter, and ultra-high tensile steel is increasingly being used for stiffeners and inner members. On the other hand, outer panels are becoming thinner, and the number of thin-thick-thick three sheets stacks with high sheet thickness ratio (hereinafter referred to as difficult sheet stack) in which it is difficult to ensure the weld diameter of the thin plates while suppressing expulsion is increasing. In this paper, we report on a new spot welding method (CDC welding method) developed to solve this problem, its welding mechanism, its effect of expanding the range of weldable sheet combinations and its effect of suppressing expulsion, in comparison with conventional direct current inverter (hereinafter referred to as DC) welding.

Development of Resistance Spot Welding Technology Using Pulsed Current Waveform Control and Automatic Off-Time Control for Three Sheets Stacks with High Sheet Thickness Ratio (Part 2)
-CDC New Spot Welding Technology-

Shinya Watanabe･Hitoshi Saito･Xihao Tan (Honda motor)･Hiroki Toyoda･Rinsei Ikeda (Osaka Univ.)

As more and more cars are being converted to BEVs, vehicle body requirements for protecting passengers and batteries are becoming stricter, and ultra-high tensile steel is increasingly being used for stiffeners and inner members. On the other hand, outer panels are becoming thinner, and the number of thin-thick-thick three sheets stacks with high sheet thickness ratio (hereinafter referred to as difficult sheet stack) in which it is difficult to ensure the weld diameter of the thin plates while suppressing expulsion is increasing. In this paper, we report on a new spot welding method (CDC welding method) developed to solve this problem, its welding mechanism, its effect of expanding the range of weldable sheet combinations and its effect of suppressing expulsion, in comparison with conventional direct current inverter (hereinafter referred to as DC) welding.